The invention disclosed relates to lubricated rollers of the type featuring a fixed overhung shaft and rolling bearings, and particular, the top rollers of crawler tracks.
The prior art embraces top rollers for the tracks of crawler tractors or other crawler vehicles, comprising a shaft which is mounted to the vehicle in overhung fashion and which carries a roller body that turns idle around the shaft. The roller body is heat-treated steel and exhibits specially machined cylindrical surfaces over which the track is made to pass; such surfaces are bordered by peripheral rims that keep the track properly aligned.
The body of the roller is entirely hollow, and creates an internal chamber in which a permanent supply of lubricant is contained.
Rotation of the body in relation to the shaft is obtained by locating a pair of rolling bearings in between the two; these may be either roller or ball type, designed to withstand radial and thrust loads alike, and are lodged in seats created in the bore of the roller for this very purpose. The outer ring of each bearing is pressed into a respective seat, and thus remains integral with the roller body; axial retaining, or limiting means, namely, shoulders incorporated into the surface of the roller bore, prevent the bearing from shifting axially toward the center of the roller.
Further, external axial limiting means integral with the shaft are provided for the purpose of preventing the bearings from drifting axially away from the center of the roller.
The bearings are therefore retained axially between the radial shoulders of the roller body and the external limiting means, and the roller itself is locked axially between the bearings.
The chamber containing the lubricant is a complete enclosure, bounded at the overhung end by a cover, bolted to the roller body in conjunction with seals; in some prior art embodiments this outer cover also functions as an external bearing retainer.
At the end of the shaft which is anchored, the lubricant chamber is enclosed by a special seal located between the relative bearing and an annular bracket which exhibits a C- or L-shaped section and is locked to the shaft by pins or other means.